[libvirt] [PATCH] Do not search xenstore for disk device IDs

[Jim Fehlig]

Disk devices can be referenced by name in Xen, e.g. when modifying
their configuration or remvoving them.  As such, don't search
xenstore for a device ID corresponding to the disk device.  Instead,
search the disks contained in the domain definition and use the
disk's target name if found.

This approach allows removing a disk when domain is inactive.  We
obviously can't search xenstore when the domain is inactive.
---
 src/xen/xend_internal.c |   38 +++++++++++++++++++++++---------------
 1 files changed, 23 insertions(+), 15 deletions(-)

diff --git a/src/xen/xend_internal.c b/src/xen/xend_internal.c
index 9d95291..d0d32e2 100644
--- a/src/xen/xend_internal.c
+++ b/src/xen/xend_internal.c
@@ -93,6 +93,7 @@ xenDaemonFormatSxprOnePCI(virConnectPtr conn,
 
 static int
 virDomainXMLDevID(virDomainPtr domain,
+                  virDomainDefPtr domDef,
                   virDomainDeviceDefPtr dev,
                   char *class,
                   char *ref,
@@ -4212,7 +4213,7 @@ xenDaemonAttachDeviceFlags(virDomainPtr domain, const char *xml,
 
     sexpr = virBufferContentAndReset(&buf);
 
-    if (virDomainXMLDevID(domain, dev, class, ref, sizeof(ref))) {
+    if (virDomainXMLDevID(domain, def, dev, class, ref, sizeof(ref))) {
         /* device doesn't exist, define it */
         ret = xend_op(domain->conn, domain->name, "op", "device_create",
                       "config", sexpr, NULL);
@@ -4306,7 +4307,7 @@ xenDaemonDetachDeviceFlags(virDomainPtr domain, const char *xml,
                                         def, xml, VIR_DOMAIN_XML_INACTIVE)))
         goto cleanup;
 
-    if (virDomainXMLDevID(domain, dev, class, ref, sizeof(ref)))
+    if (virDomainXMLDevID(domain, def, dev, class, ref, sizeof(ref)))
         goto cleanup;
 
     if (dev->type == VIR_DOMAIN_DEVICE_HOSTDEV) {
@@ -6048,6 +6049,7 @@ error:
  */
 static int
 virDomainXMLDevID(virDomainPtr domain,
+                  virDomainDefPtr domDef,
                   virDomainDeviceDefPtr dev,
                   char *class,
                   char *ref,
@@ -6056,27 +6058,33 @@ virDomainXMLDevID(virDomainPtr domain,
     xenUnifiedPrivatePtr priv = domain->conn->privateData;
     char *xref;
     char *tmp;
+    unsigned int i;
+    virDomainDiskDefPtr disk;
 
     if (dev->type == VIR_DOMAIN_DEVICE_DISK) {
+        if (dev->data.disk->dst == NULL)
+            return -1;
         if (dev->data.disk->driverName &&
             STREQ(dev->data.disk->driverName, "tap"))
             strcpy(class, "tap");
         else
             strcpy(class, "vbd");
 
-        if (dev->data.disk->dst == NULL)
-            return -1;
-        xenUnifiedLock(priv);
-        xref = xenStoreDomainGetDiskID(domain->conn, domain->id,
-                                       dev->data.disk->dst);
-        xenUnifiedUnlock(priv);
-        if (xref == NULL)
-            return -1;
-
-        tmp = virStrcpy(ref, xref, ref_len);
-        VIR_FREE(xref);
-        if (tmp == NULL)
-            return -1;
+        /* For disks, the device name can be used directly.
+         * If disk device exists in domain definintion,
+         * copy it to ref and return success.
+         */
+        for (i = 0; i < domDef->ndisks; i++) {
+            disk = domDef->disks[i];
+            if (STREQ(dev->data.disk->dst, disk->dst)) {
+                tmp = virStrcpy(ref, disk->dst, ref_len);
+                if (tmp == NULL)
+                    return -1;
+                else
+                    return 0;
+            }
+        }
+        return -1;
     } else if (dev->type == VIR_DOMAIN_DEVICE_NET) {
         char mac[30];
         virDomainNetDefPtr def = dev->data.net;
-- 
1.6.0.2